The immune system in animals is fortified as a precaution in times of energy shortage by a hunger- or stress-induced mechanism that releases antimicrobial peptides.

"Bonn researchers have discovered an elementary mechanism which regulates
vital immune functions in healthy people. In situations of hunger which
mean stress for the body's cells, the body releases more antimicrobial
peptides in order to protect itself.

"…The biomedical researchers from the LIMES Institute at the University
of Bonn have been able to show in fruit flies but also in human tissue
that this natural immune defence system is linked directly to the
metabolic status via the insulin signalling pathway.

"If we have not eaten for a while or have to climb many stairs, the
energy level of our cells drops and with it the level of insulin. The
researchers from Bonn have now discovered that in the case of a low
insulin level the FOXO transcription factor is activated. A
transcription factor can switch genes on and off. FOXO switches genes
for immune defence proteins on when energy is needed. These
antimicrobial peptides (AMP) -- not to be confused with antibodies --
are subsequently jettisoned by the body's cells. They destroy possible
pathogens by dissolving their cell walls.

"…In situations of hunger which mean stress for the body cells, the body
releases antimicrobial peptides as a precaution in order to protect
itself." (Science Daily 2010)

Application Ideas: Warning system for buildings, bridges, other large structures to warn of excessive stress loads or damage. Example of just-in-time manufacturing, where materials are produced only when certain conditions require them.